Anthrax

Search

Find an explanation of your pathology test

What is anthrax?

Anthrax is an infection caused by a bacterium, Bacillus anthracis. The infection can take three forms depending on the affected part of the body: cutaneous (on the skin), inhalational, and gastrointestinal. B. anthracis is a spore-forming microorganism that lives in the soil. The spore is extremely hardy and can lie dormant yet alive for many years. The bacterium primarily infects wild and domesticated grazing animals, such as cattle, sheep, and goats. Humans can then become infected by handling the animals or their hair, hide, or meat. Natural anthrax infection is not contracted through drinking milk from an infected animal. Human-to-human transmission is exceedingly rare.

Only cutaneous anthrax has ever been recorded from humans in Australia. For this reason alone, a single case of either inhalational or gastrointestinal anthrax should be viewed with a high index of suspicion of deliberate release of B. anthracis. In the 1920s, cutaneous cases were associated with infected shaving brush bristles. In the early 1960s a farm worker died from the complications of cutaneous anthrax, contracted after conducting post mortems on sheep, after he refused early medical treatment. Only ten human cases were reported in Australia from 1977 to 2010, one each in 2006 and 2007. Anthrax has been nationally notifiable since 1 January 2001.

Anthrax received substantial attention in 2001 when multiple people were exposed to anthrax spores sent through the US mail. Eleven cases were diagnosed as cutaneous and a further eleven as inhalational, with five fatal cases in the latter group.

The US cases in 2001 are believed to have been intentionally caused and raised concerns about the use of anthrax as a weapon. Many countries have investigated and experimented with anthrax as a biological weapon. Anthrax is not transmitted from one human to another, but it makes a potentially effective weapon because it causes deadly infections and the B. anthracis spores are hardy enough to survive dissemination through various routes. These characteristics also make it a potential weapon for terrorists.